failed to open rowset - When grouping

[obryant32]

I have a report that I created in Crystal X. I wrote a stored procedure in Microsoft SQL server 2000 that returns the data set. The wierd thing is that the Stored Procedure and the report work fine until I try to use one of the fields to do some grouping. At that point I get an error that says "failed to open rowset". Any ideas?

Thanks
Matt